This is my say on the topic of Deductive vs Inductive Learning.
Deductive learning is based on learning the rules first and then putting it into practice. Inductive allows the learner to figure out the grammar rule for themselves by analyzing examples.
It appears that many teachers prefer the deductive method, and mostly because that is how we were taught. It also appears that most teachers agree that a mixed approach to teaching would be the most useful.
On a personal note, my wife learned English as a native language through the inductive approach and she did not appreciate it. She didn't understand grammar until she took Latin in university. There might be something to this deductive approach.